By default all annotations are markup-only in the sense that they do not have any appearance. If you want to display a highlight, range brackets or anything else, you can use the UI layers feature of RadRichTextBox. You can read more about them in this article.

Methods for retrieving the containing annotations around a particular inline. This is particularly convenient if you would like to perform checks against the caret position. First, you can obtain the current inline like this:

In order to delete an annotation, you need to obtain a reference to its range start first. After that, you can use the following method of RadDocumentEditor to remove it.

/// <summary>
/// Deletes an annotation range.
/// </summary>
/// <param name="rangeStart">The start of the range that is to be deleted.</param>
public void DeleteAnnotationRange(AnnotationRangeStart rangeStart)

Note that this method will remove the annotation, but will keep its contents. In order to delete the contents as well, you can select it and use the Delete method of the editor: